Dual ignition explosive arrangement



June 3, 1969 A. A. LAVINE 3,447,463 DUAL IGNITION EXPLOSIVE ARRANGEMENT Filed May 1, 1967 Sheet of a kgz INVENTOR. Z 5 ARTHUR A. LA VINE A 7TORNEY June 3, 1969 A. A. LAVINE 3,447,463

DUAL IGNITION EXPLOSIVE' ARRANGEMENT Filed May 1, 1967 Sheet 2 of s IN VEN TOR.

: 7 warm/x? .4. (AV/NE FRAGMENT DENSITY June 3, 1969 I A. A. LAVINE 3,447,463

DUAL IGNITION EXPLOSIVE ARRANGEMENT Filed May 1. 1967 Sheet 3 or s FRAGMENT VELOCITY IN VENTOR. Aer/awe A. ZA VINE United States Patent 3,447,463 DUAL IGNITION EXPLOSIVE ARRANGEMENT Arthur Alfred Laviue, Los Augeles, Calif. (5322 Waupaca Road, Palos Verdes Peninsula, Calif. 90274) Filed May 1, 1967, Ser. No. 635,248 Int. Cl. F42b 13/48 US. Cl. 102-67 8 Claims ABSTRACT OF THE DISCLOSURE There is disclosed herein an explosive arrangement particularly suited to hand grenades, mortar shells, aerial bombs, artillary shells, armor piercing and anti-personnel weapons and the like in which the particle dispersion distribution is in a predetermined pattern comprising a small angular distribution dispersion pattern about a plane perpendicular to the line joining two detonation means coupled to a high explosive charge means. The two detonation means are detonated orientated simultaneously to generate two converging detonation fronts in the explosive charge means. When the detonation fronts meet, a Mach stem is generated. This Mach stem is generally formed in a plane midway between the two detonation means and perpendicular to the line joining the two detonation means.

The converging detonation fronts rupture the case means that encloses the explosive charge means and breaks it into a plurality of fragments. The fragments are accelerated by the converging detonation fronts into the narrow dispersion pattern about the plane and the Mach stem accelerates :the fragments that are in the region of the plane to a much higher velocity.

Attitude and trajectory control means may also be included to provide a substantially vertical descent towards the ground and maintain the equatorial plane in a substantially horizontal position.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the explosive art and more particularly to an improved armor piercing and anti-personnel weapon.

' Description of the prior art It has long been a design aim of weapons manufacturers to provide weapons which will have a more elfective result. This result may generally be construed in view of the specific design utilization-s of the weapon. For example, for anti-personnel weapons it is desired that the weapon have a high-ill performance characteristic and, of course, for armor piercing weapons it is desired that the weapon provide a high degree of armor penetration. Within these criteria it is usually desired to maintain the weight of the weapon at as low a value as possible to minimize logistics and supply problems and this is particularly true for hand-launched and personnelcarried weapons such as hand grenades.

In the field of anti-personnel and armor piercing weapons fragmenting type weapons such as hand grenades, mortar shells, etc., have often been utilized and in such fragmenting type weapons an explosive charge is detonated to rupture a metallic casing in predetermined fragmenting patterns, such as the familiar wafile grid or pineapple configuration of conventional hand grenades. The fragments are accelerated by the explosive charge and move outwardly from the point of detonation with various velocity vectors. It will be appreciated, of course, that in general the higher the momentum of each fragment in the plurality of fragments the greater will be the kill probability, for example, in an anti-personnel weapon,

if the fragment hits personnel. Similarly, the greater the momentum associated with the fragment in the plurality of the fragments, the greater will be the probability of armor piercing for such armor piercing weapons.

In the past, however, many weapon systems have utilized substantially isotropic fragment distribution, i.e., the fragment-s from the plurality of fragments in the case of the weapon are accelerated equally in radial directions from the point of detonation thereby providing a comparatively low fragment density or isotropic distribution is obtained. Shaped charges, of course, have often been utilized for armor piercing applications but the requirements for shaped charging in a weapon have generally limited their utility as an anti-personnel weapon because of low hit probability.

When proper fusing and/ or detonation initiation means are provided so that the point of detonation with respect, for example, to the ground, may be predetermined even to a rough order of magnitude, it is apparent that an isotropic fragment distribution is not necessarily the most effective fragment distribution for either anti-personnel or even armor piercing characteristics since the average size of personnel and the rough average size of armored vehicles is known and it is desired that the particle distribution be substantially concentrated in a solid angle falling within such precalculated sizes of the target. Thus, it may be considered that it has long been desired to provide some form of focusing effect for the fragments in the plurality of fragments generated upon the detonation of the explosive charge in the weapon. Further, if the momentum of the fragments may be increased by, for example, increasing the velocity thereof, there is then provided both a higher kill probability due to the greater number of fragments in the desired solid angle and the fragments therein are also at a higher momentum.

SUMMARY OF THE INVENTION Accordingly, it is an object of applicants invention to provide an improved Weapon.

It is another object of applicants invention to provide an improved explosive fragmenting weapon having a greater kill probability.

It is another object of applicants invention to provide an explosive fragmenting weapon wherein the fragments are distributed in a predetermined solid angle from the point of detonation to increase hit probability.

It is yet another object of applicants invention herein to provide an explosive fragmenting weapon wherein the fragments are distributed within a predetermined distribution pattern from the point of explosion and are accelera ted therefrom to generally high velocities for greater penetration.

The above and other desiderata are achieved, according to one embodiment of applicants invention herein, by providing a fragmenting case means containing an explosive. For convenience applicant Will describe this preferred embodiment of his invention as incorporated in a hand grenade that is designed to be hand-launched. It will be appreciated, of course, that the description of this preferred embodiment of applicants invention is not a limitation on the structure or the invention thereof but is merely selected for illustration of one application of applicants invention.

The case means of the hand grenade is provided with a predetermined fragment pattern for providing a plurality of fragments upon rupturing of the case means. Rupturing of the case means is achieved by the detonation of an explosive charge means contained therein. Thus, the case means has walls defining an interior explosive receiving cavity and the explosive charge means is contained within the cavity.

Detonation means are also provided for exploding the explosive charge means and in this embodiment of applicants invention two detonation means are coupled to the explosive charge means in a preselected spaced apart array.

The spaced apart array is such that upon detonation of the two detonation means there is generated within the explosive charge means two converging detonation fronts. In the preferred embodiment of applicants invention the two detonation means are equally spaced from a median or equatorial plane of the explosive charge means so that the two detonation fronts meet substantially in the middle of the explosive charge.

To achieve this arrangement, of course, it is necessary that there be provided initiation means for substantially simultaneously initiating the two detonation means.

When the two converging detonation fronts meet in the quatorial plane of the weapon, there is generated a Mach stern and as the Mach stem moves toward the periphery of the explosive charge means the usual Mach stern high-pressure high-gas velocity is provided.

The converging detonation fronts explode the case means to rupture the structure and thereby provide the plurality of fragments. However, the direction of the converging detonation fronts focuses virtually all of the particles of the case means into a substantially narrow angular dispersion around the equatorial plane. Further, the Mach stem itself generates a fragment distribution substantially in the equatorial plane and the fragments lying in and immediately adjacent to the equatorial plane of the weapon that are acted upon by the Mach stern are accelerated thereby to velocities substantially greater than the velocities of the fragments in other regions. Thus the first portion of the plurality of fragments which may comprise the fragments of the case means lying in regions from the poles to regions adjacent the equatorial plane of the weapon are substantially focused in the narrow solid angle around the equatorial plane at a high velocity and other portions of the plurality of fragments being those portions of the case means lying substantially on and immediately adjacent to the equatorial plane are accelerated in the direction of the equatorial plane at substantially greater velocities than the first portion of the plurality of fragments.

When applicants explosive arrangement invention is utilized in a hand grenade, it is desired that the equatorial plane be substantially horizontal upon detonation and that the detonation occur above ground level, for example, but within a few feet thereof. This will provide that the small solid angle subtended by the fragment distribution pattern is oriented to provide a high-kill probability when the grenade is utilized as an anti-personnel weapon. That is, the sharp focusing of the fragments in the narrow solid angle concentrates most of the plurality of fragments from the weapon in a region where they are most likely to encounter enemy personnel. The fragments that are accelerated by the Mach stem have a much greater momentum and therefore are not only effective to increase the kill probability but also are more effective against armored vehicles and the like in that they can provide a greater penetration thereof.

To achieve this desired substantially horizontal alignment of the equatorial plane of the weapon it is desired that there be provided trajectory and attitude control means so that during the descent of the weapon it descends towards the ground in a substantially vertical line no matter how the weapon was originally launched and that the equatorial plane be maintained substantially horizontally thereby. To achieve this trajectory and attitude control applicant, in one embodiment of his invention, includes a shuttlecock stabilization system attached to the external surfaces of the case means in regions adjacent one of the poles thereof, which are 90 in angular displacement from the equatorial plane thereof. The shuttlecock may be of a ringed-fin type arrangement and applicant has found that such an arrangement provides a substantially vertical descent after an initial,

for example, parabolic trajectory, which would be obtained upon a hand-launched, and also stabilizes the attitude of the weapon so that the equatorial plane is substantially horizontal with respect to the direction of the gravity force.

In other embodiments of applicants invention there are provided variations in the case means shape and configuration to provide an even greater kill probability and higher momentum in the fragments and also other forms of trajectory and attitude control.

The foregoing and other embodiments of applicants invention illustrating the advantages and superiority of applicants improved explosive arrangement of the present invention will become more readily apparent when the following detailed description of the several embodiments thereof as shown on the accompanying drawings wherein similar refereince characters refer to similar elements throughout. It is to be understood, however, that such embodiments and the structure associated therewith are shown by way of illustration only, to make the principles and practice of the invention to adaptation for the specific applications shown and described or to utilization of the specific structural materials hereinafter set forth.

Further, the various design configuration details forming a part of the structure of applicants invention may be readily interchanged between the various embodiments thereof as may be desired and therefore description of particular structural detail in one embodiment of applicants invention is not to be interpreted as limiting such structural detail to that particular embodiment unless, of course, the structure of that embodiment requires such limitation. For example, the various attitude and trajectory control means may equally well be used with any of the embodiments of the applicants invention herein. Similarly, the various initiation means may equally well be interchanged to provide the desired initiation characteristics.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is -a sectional view illustrating one embodiment of applicants invention herein;

FIGURE 2 is a view along the line 2-2 of FIGURE 1;

FIGURE 3 illustrates another embodiment of applicants invention herein",

FIGURE 4 is a pictorial representation of the fragment dispersion pattern according to applicants invention herein;

FIGURES 5 and 6 are graphical representations of various performance characteristics of applicants invention herein;

FIGURES 7, 8 and 9 illustrate trajectory and attitude control means useful in the practice of applicants invention herein; and

FIGURE 10 illustrates another embodiment of applicants invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before providing a detailed description of the preferred embodiments of applicants invention as shown on the accompanying drawing, it will be noted that applicant has presented for illustration and description a hand grenade as illustrative of a utilization of a weapon incorporating applicants invention. However, it will be appreciated, utilization of the hand grenade as one weapon in which applicants invention may be utilized is not to be interpreted in a limiting or restricting sense but rather, as noted above, applicants invention herein may equally well be embodied and utilized in many other weapons such as mortar shells, rifle-launched grenades, aerial bombs, artillery shells and the like. Thus, wherever it is desired to provide a sharp focusing of the fragments in a Weapon in a comparatively narrow solid angle with associated high momentum of each fragment, applicants invention herein may be so utilized.

Referring now to FIGURES 1 and 2 there is shown one embodiment of applicants invention generally designated 10. The explosive arrangement shown in FIG URES 1 and 2 may be a weapon such as a hand grenade comprised of a case means 12 having external wall surfaces 14 that are provided with grooves 16 in a preselected pattern that, upon rupture of the case means 12, provides a plurality of fragments depending upon the particular fragment pattern on the exterior surfaces 14 of the case means 12. For example, the fragment pattern provided by the groove 16 may be the conventional waffle iron or pineapple" type .commonly utilized in many hand-launched grenades.

The case means 12 is also provided with internal surfaces 18 of the wall 20 thereof and the internal surfaces 18 define an interior explosive receiving cavity 22.

Explosive charge means 24 is positioned within the interior explosive receiving cavity 22 and, for the embodiment shown in FIGURES 1 and 2, the exterior wall surfaces 26 of the explosive charge means 24 are adjacent and in substantially continuous contact with the internal surfaces 18 of the wall 20 of the case means 12 throughout the extent thereof.

A pair of detonation means 28 and 30 are provided in the explosive receiving cavity 22 and coupled to the interior surfaces 18 of the wall means 20 of the case means 12 and project into the explosive charge means 24.

The explosive receiving cavity 22 is, in this embodiment of applicants invention, spherical and the detonation means 28 and 30 are diametrically opposed to each other at opposite ends of the axis 30' which, in this embodiment of applicants invention, also defines the diameter of the explosive charge means 24. The intersection of the explosive charge means 24 and the axis 32 define, for convenience in description, poles of the weapon 10 and, similarly, the plane through the center thereof designated 34 in FIGURE 1 that is perpendicular to the axis 32 may be defined as an equatorial plane. It will be appreciated that the use of the terms poles and equatorial plane are for convenience in the description of the various embodiments of applicants invention herein and not intended to be construed as limiting to applicants invention. Thus, the equatorial plane 34 is, in the preferred embodiments of applicants invention, a plane that is the perpendicular bisector of the line joining the two detonation means 28 and 30.

An initiation means, generally designated 36 is provided to insure substantially simultaneous initiation of the two detonator means 28 and 30. A single point initiator 38 is pro-vided as part of the initiation means 36 and a single point initiator 38 is an explosive that is actuated to provide, ultimately, the explosion of the explosive charge means 22. The single point initiator 38 is connected to the two detonation means 28 and 30 by, for example, prima cord or mild detonating fuses 40' and 42, respectively, which may be enclosed in a tube means 44 and 46, respectively. Prima Cord is a trademark of the Ensign- Bickford Co. and Mild Detonating Fuse is a trademark of the E. I. duP-ont de Nemours and Co. The two detonation means 28 and 30 are of the type that upon receipt of the explosion from the mild detonating fuse 40 or 42 from the low intensity detonation therein to a high intensity detonation therein. The single point initiator 38 is spaced substantially equally from the two detonation means 28 and 30 so that in the path lengths of the mild detonating fuses 40 and 42 are substantially equal. Therefore, the single point initiator 38 is approximately on the equatorial plane 34.

When the two detonation means 28 and 30 are substantially simultaneously detonated, there is generated two converging spherical detonation fronts within the explosive charge means 24. The various lines of progress of these detonation fronts are indicated by the detonation front lines 48a, 48b, 48c, and 48d. The detonation fronts are substantially identical from the detonation means 28 and those generated by the detonation means 30.

As the detonation fronts 48 converge toward the equatorial plane 34 in the explosive charge means 24, the case means 12 is ruptured along the score line 16 to provide a plurality of fragments. Further, as the detonation fronts, which in this embodiment of applicants invention are spherical, converge on the equatorial plane 34 a. generally toroidal-shaped Mach stem is generated therebetween symmetrically about the equatorial plane 34. FIG- URE 1 illustrates the Mach stem in three diflerent stages of its development and as can be seen, it is generated first adjacent the center of the explosive charge means 24 and moves radially outward therefrom. As the Mach stem progresses radially outwardly, it will be appreciated, in this embodiment of applicants invention, it is in the form of an enlarging torus progressing towards the edged portions 26 of the explosive charge means 24. The Mach stem is a high-density high-pressure high-velocity well-defined gas region which, upon contact with the interior surfaces 18 of the wall means 20 of the case means 12, accelerates the fragments that are on and generally adjacent to the equatorial plane 34 to extremely high fragment velocities which travel generally radially outwardly in the plane of or the equatorial plane 34.

The early travere of the detonation fronts 48 through the explosive charge means 24, accelerate the fragment adjacent the poles in the direction of the equatorial plane 34 at comparatively low velocities and, as the detonation fronts progress towards the equatorial plane 34, the velocity imparted to the fragments as the fragments are closer to the equatorial plane 34 becomes greater and the fragments are generally confined to a comparatively small solid angle of dispersion as indicated at 50. The solid angle of dispersion of the particles 50 is centered around the equatorial plane 34 and a first portion of the plurality of fragments from the case means 12 are accelerated to high velocities within the solid angle of dispersion 50. This provides a very high density of fragments within the solid angle 50 and thereby achieves a focusing effect of the fragments to increase the hit probability and thus the kill probability due to the explosion of the weapon 10. Further, in the equatorial plane 34 in regions adjacent thereto the fragments are accelerated to extremely high velocities due to the Mach stem 49 and therefore such extremely high velocity fragments provide a greater probability of armor penetration.

For example, in a grenade such as that shown in FIG- URE 1, wherein the diameter of the explosive charge means 24 is on the order of 2 inches and the thickness of the wall 20 of the case means 12 is on the order of one-eighth of one inch. Applicant has found that the solid angle dispersion 50 is on the order of 24 degrees, 12 degrees above and 12 degrees below the equatorial plane 34 with an explosive charge 24 fabricated from octol, the two detonating means 28 and 30* being tetryl and the case means 12 being fabricated from Haynes 25 metal, a high cobalt alloy, properly grooved by groove 16 to provide the plurality of fragments.

FIGURE 3 illustrates in the embodiment of applicants invention wherein an even greater fragment density is achieved in the small solid angle of dispersion of the fragments. The embodiment 60 of applicants invention shown in FIGURE 3 is substantially similar to the embodiment 10 shown in FIGURES 1 and 2 as comprised of a case means 62 having walls 64 with an external surface 66 groove by groove 68 to provide a predetermined fragment pattern upon explosion. The walls 64 have interior surface portions 70 defining, in this embodiment of applicants invention a spherical explosive receiving cavity 72 in which there is an explosive means 74 having external wall 76 adjacent and in contact with the interior Wall 70 of the case means 62 throughout the extent thereof. A pair of boosters 7'8 and 80 are provided in the explosive receiving cavity 72 coupled to the internal wall surfaces 70 of the walls 64 of the case means 62 opposite poles defined by the diameter 82 of the spherical explosive receiving cavity 72.

Simultaneous initiation of the two detonation means 78 and 80 may be achieved by an initiation means 84 comprised of a single pont initiator 86 and the mild detonating fuse branches 88, 90 and 92. It can be seen from FIGURE 3 the mild detonating fuse branches 88, 90 and 92 are within the hand grenade 60 and are not external to the case means 62 as, for example, the initiation means 36 shown in FIGURE 1. However, because of the position of the mild detonating fuse branches 88, 90, and 92 within the explosive charge means 74 applicant has found that when the initiating means is in contact with the main explosive charge means it is desirable to utilize mild detonating fuse rather than prima cord, in order to assure that the explosive charge means 74 is detonated due to the two detonation means 78 and 80 in order to provide the two converging spherical detonation fronts. It will be appreciated that while the branch 88 fro-m the single point initiator 86 to the branches 90 and 92 may be of any desired length, from the intersection thereof to each of the detonation means 78 and 80 the length of the mild detonating fuse branch 90 and 92, respectively, must be the same length so that the two detonation means 78 and 80 will be detonated simultaneously and thereby provide, ultimately, the Mach stem in the equatorial plane 96 of the weapon 60. In this embodiment of applicants invention shown in FIG- URE 3 as well as in the embodiment shown in FIGURE 1, it will be appreciated, that the fragment pattern should be such that a thickened section such as the sections 69 lie on the equatorial plane 96 in order that the maximum benefit from the Mach stem be achieved through the acceleration to high velocities of the thick fragments 69 lying directly on the equatorial plane. That is, it is desired that the grooves 68 do not extend peripherally around the equatorial plane 96 or immediately adjacent thereto.

The above relationship holds true for all embodiments of applicants invention.

It will be appreciated that the initiation means 84 serves the same function as the initiation means 36 shown in FIGURE 1. That is, it is to provide the dual simultaneous ignition to the explosive charge means in order to provide the converging detonation fronts. Thus the two detonation means 78 and 80, the single point initiator 86 and explosive charge means 74 may, respectively, be similar to the two detonation means 28 and 30, the single point initiator 38 and explosive charge means 24 shown in FIGURE 1.

In this embodiment of applicants invention, the thickness of the wall 64 of the case means 62 is not constant and the external surfaces 66 thereof define an oblate spherical surface. Thus since the internal surfaces 70 define a sperical explosive receiving cavity 72, the wall thickness of the wall 64 of the case means 62 decreased monotonically from the equatorial plane 96 to the axis 82. Thus, as can be seen from FIGURE 3, there is a greater amount or mass of metal in regions adjacent the equatorial plane 96 than in regions adjacent the axis 82 in the case means 62.

Upon initiation of the detonation provided by the detonation means 78 and 80 two converging detonation fronts are generated within the explosive charge means 74 towards the equatorial plane 96 from the poles defined by the axis 82. The converging spherical detonation fronts, when they meet at the equatorial plane 96, generate a Mach stem generally designated 98 in FIGURE 3 moving radially outwardly from the center to the external surfaces 76 of the explosive charge means 72. The Mach stem 98 is similar to the Mach stem 49 described above and produces the same extremely high velocity effect upon contact with the case means 62 in that the fragments adjacent to the equatorial plane 96 as contacted by the well defined Mach stem 98 are accelerated to extremely high velocities in the direction the same as or parallel to equatorial plane 96.

By providing the tapered wall of the case means 62 as shown on FIGURE 3 the momentum of the fragments contained within the solid angle of dispersion 100 is enhanced over the momentum obtained for a uniform wall thickness case means. Thus the low velocity associated with the fragments from the regions adjacent the poles defined by the axis 82 result in comparatively low momentum particles which, in general, at a given distance from the point of explosion are outside of the solid angle dispersion 20 and provide the increasingly more massive fragments as the fragments come from regions closer to the equatorial plane 96 with higher momentum and they are substantially concentrated within the solid angle dis persion 100 which is centered about the equatorial plane 96.

From the description of applicants invention shown in FIGURES 1 and 3 it can be seen that there is at least one plane of symmetry in each of the explosive arrangements 10 and 60. The plane of symmetry, of course, may be defined as including the 'axis of the explosive charge means and on which the two detonation means are provided.

It will be appreciated that, for example, more than two detonation means may also be provided, for example, in the same plane as the detonation means but spaced degrees therefrom. For this arrangement there would then be generated substantially four spherical detonation fronts converging toward the center of the explosive charge means with the result in modification of the distribution pattern of the fragments and the velocities associated with the Mach stem generated.

FIGURES 5 and 6 are graphical representations of some of the characteristics associated with applicants improved explosive arrangement. The graphs of FIGURES 5 and 6 would be applicable to the arrangements of applicants3 invention such as those illustrated in FIGURES 1 and FIGURE 5 shows the relationship between the density of the fragments from the case means as a function of the position of the fragment relative to the equatorial plane. Thus the equatorial plane as designated by the letters EP on FIGURE 5 shows the greatest fragment density and the fragment density per unit solid angle decreases between the equatorial plane and the poles, which are indicated by the letter P. The abscissa of the graph of FIGURE 5 may be considered as a flat target plate spaced from the explosive arrangement in which the fragments therefrom are imbedded after detonation. Thus there are comparatively few fragments in the regions comprising planes parallel to the equatorial plane and adjacent the poles and the density of the fragments increases as these planes are moved from the poles towards the equatorial plane. Therefore, as indicated above, there is provided a focusing effect of the fragments and the fragments are substantially concentrated in the abovementioned narrow solid angle of dispersion centered around the equatorial plane. With a symmetrical configuration it will be appreciated that the curve of FIGURE 5 is also symmetrical about the equatorial plane.

The curve of FIGURE 6 illustrates the fragment velocity as a function of the relative position of the fragment with relation to the poles and the equatorial plane. The velocity of the fragments from regions adjacent the poles is comparatively low and increases as the position of the fragment is closer to the equatorial plane. Thus the abscissa of the graph of FIGURE 6 may be considered a flat target spaced from the explosive arrangement of applicants invention to receive the fragments upon explosion thereof. The velocity of the fragments increases drastically in regions adjacent the equatorial plane due to the abovedescribed effect of the Mach stem. Thus there is superimposed upon the first preselected fragment velocity distribution the sharp spike to the Mach stern. Thus the the fragments in the equatorial plane and immediately adjacent thereto are accelerated to a very high velocity to provide a high momentum thereof for increased armor penetration and kill probability.

For the specific example described above, applicant has found that the fragment velocity in or adjacent to the equatorial plane will be on the order of 9,000 feet per second. The dotted line curves B on FIGURES and 6 illustrate the fragment density distribution and fragment velocity distribution with conventional hand grenades known in the prior art. Thus the kill probability provided by applicants improved explosive arrangement is greatly enhanced over the kill probability of the more conventional isotropic fragment density distribution and velocity distribution. To achieve the most useful results from this focusing effect and to provide the greatest kill probability against personnel as well as maximum armor piercing effect, it is desired that the equatorial plane be maintained, at the time of explosion, substantially horizontal. FIGURE 4 illustrates the relationship of applicants improved explosive arrangement, which may be the explosive arrangement 60 shown in FIGURE 3 as it approaches the ground 102. Thus the equatorial plane 96 is substantially parallel to the ground 100 immediately prior to explosion of the explosive arrangement 60 and the cone of the solid angle of dispersion 100 of the fragments from the case 62 is centered around the equatorial plane 96 and for the example described above has a solid cone angle D of approximately 24 degrees and a half cone angle above and below the equatorial plane 96 E on the order of 12 degrees. If the explosion of the explosive arrangement 60 occurs within a few feet of the ground applicant prefers to include a trajectory and attitude control means in the practice of his invention. Thus the attitude of the explosive arrangement should be controlled so that the equatorial plane thereof is substantially horizontal and that the descent immediately prior to explosion is substantially vertical.

For a hand-launched grenade, aerial bombs or artillery shells, applicant has found that the shuttlecock technique may be conveniently utilized to provide the trajectory and attitude control.

FIGURE 7 illustrates an embodiment of applicants invention, generally designated 110 in which the explosive arrangement 112 may be, for example, substantially identical to the explosive arrangement 60 shown in FIGURE 3 or the explosive arrangement 10 shown in FIGURE 1,

is both trajectory and attitude control by a trajectory and attitude control means 114 coupled to the external surfaces 116 of the wall 118 of the case means v120 defining the explosive arrangement 112. The external surface 116 may be scored or otherwise marked to provide, upon explosion of the explosive arrangement 112 the plurality of fragments as abovedescribed.

In this embodiment of applicants invention, the trajectory and attitude control means 114 is designed to provide a substantially vertical descent towards the ground .102

as indicated by the arrow 122 during the period at least immediately prior to the explosion thereof. Thus, for example, if the explosive arrangement 112 may be considered a hand-launched hand grenade it is generally thrown by personnel and during the first portion of the flight thereof follows a parabolic trajectory. However, due to the shuttlecock effect provided by the trajectory and attitude control means, there is provided substantially vertical descent during the descending portion of the trajectory after the parabolic rising portion thereof. Trajectory and attitude control means 114 is comprised of a stem 124 coupled to the external surface 116 of the wall 118 in the case means 120 and a plurality of fins 126 spaced apart from the case means v120 and extending outwardly from the stem means 124. A ring member 128 is coupled to the extremities of the fins 126 to provide a ringed fin arrangement and, applicant has found, the ringed fin structure abovedescribed provides satisfactory trajectory and attitude control. It has been found that for a hand-launched grenade against personnel, it is desirable that, with the solid angle cone of dispersion of the fragments 130 being on the order of that abovedescribed, i.e., approximately 24 deggees centered around the equatorial plane 132 the explosion height should be approximatelythree feet for maximum kill probability. Conventional time fusing as currently utilized in hand grenades to provide the detonation of the two detonation means that may be included in the explosive arrangement 112 that is based upon a time delay from the time of throwing thereof may equally well be utilized with applicants improved explosive arrangement 112 since comparatively inexperienced personnel can rapidly learn the proper manner in which to throw the grenade so that for the particular time delay associated therewith the explosion thereof will be within the abovementioned three feet or so from the ground 102.

The trajectory and attitude control means 114, it will be appreciated, is a rigid structure and extends from the explosive arrangement .112. Such an extension may in some embodiments and applications of applicants inventions be desirable. Accordingly, other trajectory and attitude control means may be utilized that does not require extensive substantially rigid protrusions. One such arrangement is illustrated in FIGURES 8 and 9. As shown on FIGURES 8 and 9 there is a trajectory and attitude controlled explosive arrangement covering an explosive arrangement 142 that may, if desired, be similar to the explosive arrangement 112 shown in FIGURE 7. Substantially vertical descent of the explosive arrangement 142 in the direction indicated by the arrow 122 immediately prior to the explosion thereof may be provided by the shuttlecock effect achieved through the utilization of a gas-filled balloon 144 that is coupled by a flexible tether 146 to the explosive arrangement 142.

FIGURE 9 illustrates the trajectory and attitude control means 143 in the folded or compressed condition prior to launching of the explosive arrangement 140. The gasfilled balloon means 144 is contained within a canister -145 that, upon filling of the balloon 144, is removed.

The balloon means 144 is shown on FIGURE 9 also comprises the tether means for securing the balloon means 144 to the explosive arrangement 140.

For example, when the explosive arrangement 140 is launched by hand-throwing the usual procedure for hand grenades is to pull the pin which initiates a control time delay until the detonation of the explosive charge means 140. This may be achieved by a powder train 148 having a first branch 150 burning, for example, for four seconds. During this time of four seconds the hand-launched explosive arrangement 140 is traveling in a generally parabolic arc toward the target. After four seconds, however, the portion 150 of the powder train 148 engages a thermite igniter 152 which burns through a magnesium rod 154. The magnesium rod 154 is coupled to a needle valve means 155 that is utilized to control the flow of gas from gas storage bottle means 157. The valve means 155 is kept in a seated condition on valve seat 156 by the rod means 154. However, when the magnesium rod 154 is burned through by the thermite igniter 152 the spring means 158 allows the movement of the needle valve means 155 in the direction indicated by the arrow 159 so that the needle valve means 155 is unseated from valve seat 156 to allow the flow of high pressure gas into the balloon means 144 for deployment thereof.

The second branch 151 of the powder train 148 then burns, for example for two more seconds, until it encounters the single point initiater 153 of the initiation means 161. The initiation means 161 is comprised, as the initiation means 36 in FIGURE 1 and 84 in FIGURE 3, of a single point initiater 153 and a pair of detonation means 165 and 167. The powder train 151 initiates the single point initiater 153 and then the simultaneous dual initiation of the two detonation means 165 and 167. Thus, during the last two seconds of flight of the explosive arrangement 140 the balloon means 144 is deployed to provide the shuttlecock effect and a substantially vertical descent of the explosive arrangement 140 in the direction indicated by the arrow 122. This orients the equatorial plane 169 thereof in the proper attitude to obtain the maximum benefits from applicants invention herein.

The deployed balloon 144 provides the trajectory and attitude control so that the equatorial plane of the explosive arrangement 142 is maintained substantially horizontal at least immediately prior to explosion thereof and the descent of the explosive arrangement 142 is substantially vertical immediately prior to the explosion thereof.

The abovedescribed arrangement of applicants invention has shown a substantially spherical or oblate spheroid configuration for the case means that provide for plurality of fragments. It will be appreciated that other geometrical configurations may equally well be utilized, to provide the sharp focus of the frgarnents from the case means within a comparatively narrow angular cone of dispersion centered about an equatorial plane. FIGURE illustrates an embodiment of applicants invention, generally designated 160 in which there is provided a substantially right circular cylindrical case means 162 having walls 164 with external surfaces 166 thereof provided with score lines 168 to provide a preselected fragment pattern thereon, which, for example, may be similar to the fragment patterns abovedescribed.

The wall 164 also is provided with interior surfaces 170 that define a generally right circular cylindrical explosive charge receiving cavity 172 in which there is a generally right circular cylindrical explosive charge means 174. The right circular cylindrical charge means 174 has external walls 176 thereof substantially in contact with the interior wall surfaces 170 of the walls 164 of the case means 162 and substantially co-extensive therewith. End caps 178 and 180 are also provided to close the top and bottom respectively of the right circular cylindrical explosive receiving cavity 172.

Initiation means 182 which may be similar to the initiation means 36 described above is provided to provide substantially simultaneous initiation of the two detonation means 184 and 186 coupled to the top and bottom, respectively, of the explosive charge means 174. The two detonation means 184 and 186 are on the axis 188 of the right circular cylindrical charge means 174 and therefore the planes of symmetry include the axis 188 and the two detonation means 184 and 186 are on the planes of symmetry and are oppositely disposed. As described above, upon simultaneous detonation of the opposed detonation means 184 and 186, there is generated converging detonation fronts in the explosive charge means 174 approaching the equatorial plane 190. Upon reaching the equatorial plane 190 a Mach stem is generated, and is generally toroidal in form extending and moving outwardly from the center of the explosive charge means 174 towards the external surfaces 176 thereof and, as described above, accelerates the fragments on and immediately adjacent to the equatorial plane 190 to comparatively high velocities. Further, the converging detonation fronts accelerate the fragments from the ruptured case means 164 into a comparatively narrow solid angle cone of dispersion 192 centered about the equatorial plane 190.

The fragment density within the solid angle cone of dispersion 192 is substantially greater than that obtained due to an isotropic distribution and due to the converging detonation fronts the momentum associated with each fragment within the solid angle cone of dispersion 192 is greater than obtained due to an isotropic fragment distribution. In addition, as described above, the very high velocity associated with the Mach stem provides fragments moving in the plane or and parallel to the plane of the equatorial plane 190 at a comparatively high velocity to increase both the armor piercing and kill probability of the explosive arrangement 160.

It will be appreciated that other geometrical configurations may equally be utilized in the practice of applicants invention herein and applicant is not intended to be limited by the description of the spherical, oblate spheroid or cylindrical shapes in the embodiments of applicants invention described above. Also, it will be appreciated, that the positioning of the detonation means to provide the converging fronts, as well as the number of such detonation means, in the explosive charge, may be varied to provide any desired dispersion pattern and concentration of fragments. Such fragment patterns may be symmetrical as with the embodiments described above, or they may be non-symmetrical as may be suitable for special applications. Further, the descent and trajectory control means may vary depending upon the particular application and may be designed to function so that the focused pattern is oriented in any desired attitude.

From the above, it can be seen that applicant has provided an improved explosive arrangement that provides an increased hit probability and kill probability and a greater armor-piercing effect than has heretofore been attained in other weapons.

What is claimed as new and desired to be secured by the Letters Patent of the United States is:

1. A fragmenting high-velocity explosive arrangement comprising, in combination:

a metallic case means havings walls with exterior surfaces, and with interior surfaces defining an interior explosive receiving cavity, and said case means having a predetermined fragment pattern for providing a plurality of fragments upon rupturing of said case means;

an explosive charge means positioned within said interior explosive receiving cavity of said case means for rupturing said case means and imparting preselected velocities in preselected directions to said plurality of fragments, .and said explosive charge means having exterior wall surfaces and at least a portion thereof contiguous to said interior surfaces of said walls of said case means, and said exterior wall surfaces having a first detonation portion and a second detonation portion in a spaced apart opposed relationship, and said explosive charge means having .an equatorial plane intermediate said first detonation portion and said second detonation portion of said exterior wall surfaces;

at least two detonation means comprising:

a first detonation means positioned in detonation front inducing relationship to said first detonation portion of said exterior wall surfaces of said explosive charge means;

and a second detonation means positioned in detonation front inducing relationship to said second detonation portion of said exterior wall surfaces of said explosive charge means;

and said at least two detonation means for inducing a pair of converging detonation fronts in said explosive charge means, and said pair of converging detonation fronts comprising:

a first spherical detonation front in said explosive charge means at said first detonation portion of said exterior wall surfaces of said explosive charge means for progression to said equatorial plane therefrom;

and a second spherical detonation frontvat said second detonation portion of said exterior wall surfaces of said explosive charge means for progression toward said equatorial plane to converge thereon with said first spherical detonation front to generate a Mach stem at said equatorial plane, and said Mach stem for progressive movement toward said exterior walls of said explosive charge means in said equatorial plane;

initiation means for providing substantially simultaneous initiation of said at least two detonation means, and said case means is ruptured to provide said plurality of fragments, and said converging detonation fronts accelerate a first portion of said plurality of fragments in a first predetermined concentrated 13 pattern and in a first predetermined velocity distribution, and said Mach stem accelerates other portions of said plurality of fragments to .a velocity greater than the velocities of the fragments in said first portion of said plurality of fragments.

2. The arrangement defined in claim 1 wherein:

said predetermined fragment pattern of said walls of said case means comprise a plurality of grooves in said external surfaces of said walls of said case means;

said case means and said interior explosive charge receiving cavity thereof have at least one plane of symmetry; and

said at least two detonation means are coupled to said external surfaces of said explosive charge means on said plane of symmetry and said preselected spaced apart array thereof is an opposed array to provide said at least two detonation fronts oppositely disposed on said explosive charge means.

3. The arrangement defined in claim 2 wherein said external surface of said walls of said case means define an oblate spheroid, said interior surfaces thereof define a spherical explosive receiving cavity:

said at least one plane of symmetry includes the minor axis of said oblate spheroid and defining a pair of poles of said explosive charge means on said minor axis thereof, and said at least two detonation means are coupled to said exterior surface of said explosive charge means on opposite ends of said minor axis on the poles;

and said Mach stem is substantially uniformly generated around the periphery of said case means in equatorial regions thereof adjacent the equatorial plane perpendicular to said minor axis; and said first predetermined concentrated pattern of said first portion of said plurality of fragments is a dispersion pattern centered about said equatorial plane and falling within a small preselected angle above and below said equatorial plane; and

said other portions of said plurality of fragments are accelerated by said Mach stem in substantially the equatorial plane.

4. The arrangement defined in claim 3 wherein:

the Wall thickness of said wall of said case means decreases monotonically from said equatorial region to said poles.

5. The arrangement defined in claim 4 and further comprising:

trajectory and attitude control means for controlling the trajectory through the air to provide a descent to regions adjacent to ground in a substantially vertical path, and said equatorial plane is oriented in a substantially horizontal alignment during at least a preselected portion of descent.

6. The arrangement defined in claim 5 wherein said trajectory and attitude control means comprises a plurality of ringed fins coupled to said external surfaces of said walls of said case means in regions adjacent one of said pair of poles.

7. The arrangement defined in claim 6 wherein said trajectory and attitude control means comprises:

an inflatable balloon means coupled to said exterior surfaces of said case means in regions adjacent one of said pair of poles; inflation means for inflating said balloon at a predetermined portion of the trajectory thereof; and control means for actuating said inflation means to inflate said balloon. 8. The arrangement defined in claim 2 wherein: said case means defines a generally tubular right circular cylindrical section having a predetermined wall thickness and an axis extending through said explosive receiving cavity; said plane of symmetry includes said cylindrical axis; said at least two detonation means are coupled to said external surfaces of said explosive charge means on opposite ends of said cylindrical axis; said Mach stem is substantially uniformly generated around the periphery of said cylindrical case means concentrated along a plane perpendicular to said axis of said cylindrical case means and substantially equally spaced between said pair of detonation means; and said first predetermined concentrated pattern of said particles in said first portion of said plurality of particles comprises a dispersion pattern centered around said equatorial plane and diverging therefrom in a small predetermined angle; and said other portion of said fragments in said plurality of fragments are accelerated to a velocity greater than the velocity of said first portion of said plurality of fragments and are substantially concentrated in the equatorial plane.

References Cited UNITED STATES PATENTS 1,225,884 5/1917 Steinmetz 10264 1,281,939 10/1918 Gieda 102-64 1,321,699 11/1919 Archer 10264 2,381,443 8/1945 Golay 10237. 2,381,443 8/1945 Golay 102-371 3,113,517 10/1963 Kelley et a1. 1024 X 3,170,402 2/1965 Morton et a1. 10270 BENJAMIN A. BORCHELT, Primary Examiner. G. H. GLANZMAN, Assistant Examiner.

U.S. Cl. X.R. 10264 

